As well known to those skilled in the art, containers designed for easy loading and unloading of freight are transported by a trailer or a ship. A trailer used for transporting containers is provided with a locking apparatus for fixedly maintaining the containers. Also, containers to be transported by a ship are provided with locking apparatuses so that the containers are locked to and unlocked from each other at their corner portions.
An apparatus for automatically locking containers to be transported by a trailer is disclosed in Korean Patent Application No. 2000-4080 filed on Jan. 27, 2000 and entitled “Apparatus for Automatically Locking Trailer Containers”. The patent application was granted a patent on Mar. 21, 2002, and the present applicant is registered on a register of that patent as one of the joint inventors.
Hereafter, the conventional apparatus for locking ship containers will be described with reference to FIGS. 1a and 1b. The apparatus includes a housing 1 which has a center opening, a rotating body 2 which is rotatably inserted through the center opening of the housing 1, upper and lower locking heads 3 and 4 which are respectively formed integrally with upper and lower ends of the rotating body 2, and a handle 5 which is coupled to a middle portion of the rotating body 2 to rotate the rotating body 2. Adjacent to a lower end of the upper locking head 3, a groove 6 is defined on an outer surface of the rotating body 2. Adjacent to an upper end of the housing 1, an insertion groove is defined on an inner surface of the housing 1. A spring 13 and a ball 14 are inserted into the insertion groove in a manner such that the ball 14 is biased by the spring 13 in a direction where the ball 14 is engaged into the groove 6 of the rotating body 2.
In the conventional locking apparatus constructed as mentioned above, in a state wherein a first container C1 is loaded on the bottom of a ship, a second container C2 is loaded on the first container C1. At this time, as shown in FIG. 1a, the locking apparatus is fitted into a first corner casting 61a which is provided on a lower surface of the second container C2. Then, the handle 5 which is directed forward is rotated rightward by a predetermined angle. By this, the rotating body 2 is slightly rotated rightward, and at the same time, the upper and lower locking heads 3 and 4 are integrally rotated rightward.
By this operation, the upper locking head 3 is partially placed on a first shoulder which is formed in the first corner casting 61a provided on the lower surface of the second container C2.
In this state, the second container C2 is lifted using a crane and loaded on the first container C1 which is already loaded on the bottom of the ship. At this time, the lower locking head 4 which is held slightly rotated through rotation of the handle 5 is fitted into a second corner casting 61b which is provided to an upper surface of the first container C1.
Thereupon, the handle 5 which is held slightly rotated is further rotated rightward, whereby the upper and lower locking heads 3 and 4 are completely placed on their respective first and second shoulders of the first and second corner castings 61a and 61b which are provided to the second and first containers C2 and C1. At this time, the ball 14 which is biased outward of the insertion groove by the spring 13 is engaged into the groove 6 of the rotating body 2 to prevent unintentional rotation of the rotating body 2.
In this way, the first and second containers C1 and C2 loaded on the ship are securely fixed to each other.
However, the conventional container-locking apparatus suffers from defects in that, since the entire locking operations are manually conducted, a great deal of time and energy are required. That is, the manual locking operations lengthen the container loading time. Also, due to the laborious and time-consuming nature of the locking operations, costs increase. Further, since a worker conducts the locking operations while on the container, a safety issue is roused.
Moreover, if the containers are not completely locked to each other, accidents may occur.